What To Expect: a visit for allergy skin testing takes 2 1/2 to 3 hours.
Preprocedure: Over the counter antihistamines need to be discontinued at least three days before testing, as must any decongestants you are taking. Prescription antihistamines , as well as Zyrtec(cetirizine) and Claritin(loratidine)should be stopped a week before testing so they do not interfere with the test results. You should continue to take your asthma medications. There is no need to fast or skip any meals before the testing is performed.